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Ford Performance Ring Gear and Pinion Kit - 3.55 Gears (99-04 GT)

Item 50166G99
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    Features & Details

    • Ford Racing Quality
    • Strong Forged Construction
    • 3.55 Gear Ratio
    • 8.8" Ring Gear Diameter
    • For Street or Track Use
    • Fits 1999-2004 GT, Bullitt, Mach 1 and Cobra Mustangs
    Improve ET's and low end torque. Are you looking to get more low end grunt off the line and lower ET's at the same time? Then look no further than installing a set of steeper gears in your Pony. Ford Racing Ring and Pinion Gears are perfect for street, road, or race use.

    Superior Quality. These Ford Racing 3.55 Mustang ring and pinion gears feature a super strong forged construction, CNC cut & lapped gear teeth, and a black oxide finish to resist corrosion.

    Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Ford Racing Speedometer Recalibration Tool is an inexpensive way to fix this issue.

    Application. This Ford Racing Ring and Pinion Gear set will fit all 1999 to 2004 V8 Mustangs including the GT, Bullitt, Mach 1 and Cobra models. A master bearing kit is recommended by most installers, especially on high mileage vehicles, see drop down option above.

    Technical Note. Installation costs will vary, but a good rule of thumb is between $250 and $300. Be sure to work with a reliable shop that you trust for installations. You can also save money on your installation labor by having your Trac-Lok rebuilt at the same time as your gears are installed, see drop down option above.

    Fitment: 1999 2000 2001 2002 2003 2004 Details

    MPN# M-4209-G355A

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Ring gear
    • (1) Pinion gear
    Installation Info
    Tech Specs

    Approximate RPM for 1999-2004 GT

    Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
    1 3700 5180 6660      
    2 2190 3065 3941 4817 5693 6569
    3 1445 2023 2601 3179 3757 4335
    4 1095 1533 1971 2408 2846 3284
    5 744 1042 1340 1638 1936 2233

    Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
    1 3109 4353 5596 6840    
    2 1697 2376 3054 3733 4412 5091
    3 1095 1533 1971 2408 2846 3284
    4 766 1073 1379 1686 1992 2299
    Will it fit my Mustang?

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        Questions & Answers (2)

        2 Top Rated Questions

        Does this require a tune after install?

        • A tune will not be required after installation. We generally recommend a Speedometer Recalibration Tool from Ford Performance which can be found here: This will re-calibrate the speedometer.

        Helpful (0)

        will these work on my 2000 v6? just wondering if i will have to get special gears for my v6 or if these are interchangeable.

        • These gears are not interchangeable into the V6 models. These are only able to fit in the GT model as the V6's will have a different size rear end.

        Helpful (0)
        Post Your Question

          Customer Reviews (9) Write a Review

          Overall Rating 4.8

          out of 5 stars

          Installation Time:Full Day

          Installation Cost:$250-$500

          • Performance Gain 4.875 4.9
          • Fit 4.875 4.9

          • 3/5

            Installation Time: Afternoon

            July 29, 2018

            ford racing gears

            set up as per ford spec with ford tools whines on decal


            Year: 2000 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            January 04, 2018

            Installed Gears with new Differential

            Everything is installed took about 5-6 hours due to the fact I was rebuilding my whole rear end. Now my 2000 GT pulls like a champ. Purchased a couple more parts from AM for my rebuild, and they all were worth it.


            Year: 2000 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Afternoon

            December 08, 2017

            Alot better than motive

            Switching out my motive 4.10s after adding boost to these. side by side the ford gears are alot better quality.


            Year: 2003 Submodel: Mach 1

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            July 28, 2017

            Amazing quality!

            These gears are amazing in quality and craftsmanship. These webt great in my daily driver, very fun with built rear end, made the car feel much more responsive and composed. Definitely worth it if you're looking for some light gears!


            Year: 2002 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Shop Install

            June 11, 2017

            Spin the gears

            They fit and worked perfect. I had a shop install them as part of a complete rebuild.


            Year: 2003 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            August 26, 2013

            3.55 ford racing gears

            With this gears gave me acceleration and also made my car quicker at the track I recommend this for any one with boost cars the need the rpm to increase their boost


            Year: 2001 Submodel: Cobra San Francisco, CA, USA

            Helpful (8)

          • 5/5

            Installation Time: Weekend

            April 28, 2012

            3.55 Ford Racing Gears

            This product was a good buy, I bought the gears and the bearing kit and everything was a perfect fit. It took one weekend to finish the install and the results were outstanding, when I punch the throttle she's gone and there's no looking back. -Mark D.


            Year: 2001 Submodel: GT New Orleans

            Helpful (6)

          • 5/5

            Installation Time: Less than 1 Hour

            December 09, 2011

            Excellent no other words are needed

            FRPP I think are the best products around. 85% of my 04 Mach 1 is from AM and FRPP either from you or direct from Ford. Thanks for all the help in the past and in the future.


            Year: 2004 Submodel: Mach 1 Reading,Pa.

            Helpful (6)

          • 5/5

            April 29, 2011

            3.55 Gears

            I have a set of these in my car. After two weeks I had somehow bent an axle (without bending the tube), destroyed my LSD, and destroyed gears. I had the 3.55s swapped in. It is a huge difference. I went 3.55 because I planned to go S/C. I am still doing S/C but planning to swap a T56 Magnum so, I am going to 3.73s. I loved the 3.55s but, want more.


            Year: 2002 Submodel: GT

            Helpful (7)

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